Heat the oil in a non-stick frying pan and over medium heat, add the potatoes, onions if using.
Cook covered with a lid, tossing every now and then for 5 - 10 minutes until the potatoes are softened. Season generously.
Next, crack the eggs into a large bowl, add a good pinch of seasoning, then whisk lightly with a fork.
When the onion and potato mixture is cooked, remove from the pan into a bowl and add the bacon to the pan. Cook the bacon for a further 2-3 minutes until crispy.
Add the potato back in the pan and toss the bacon and potato together.
Pour carefully over the potato mixture the beaten eggs.
Cook for about five minutes over medium heat until there is virtually no raw egg mixture left, pushing down the sides with a spatula for a curved edge. Invert on to a flat plate and slide back into the pan.
Cook for another 2-4 minutes until just cooked through but still very moist in the centre.
To serve, turn the omelette onto a chopping board and cut into wedges.
Serve the wedges with salad leaves.
